This is Great ! Thanks to make it happen for the STM32 free community and users. Did you have some benchmark data vs commercial RTOS like µCOSII and others in terms of numbers of tasks , footprint etc... Thank you gain.

As you can see on the STM32 the whole kernel takes just 4.5KB vs the 6.5KB required for a normal ARM7 micro controller, the STM32 also clearly outperforms them as pure speed.
The kernel size can shrink down to 1.5KB by disabling some subsystems, most applications do not require all the features enabled.

The RTOS itself has no upper limit for threads, semaphores etc, the real limit is the available memory. Each thread just requires about 56 bytes of RAM + the space required for its stack.

I cannot run direct comparisons vs other OS because there are differences in the API/architecture and one could argue the tests would be biased, however I think ChibiOS/RT is well positioned as features, footprint and performance.

I am pleased to announce that the first ChibiOS/RT stable version 1.0.0 has been released. This release has some STM32-related improvements and adds a linking exception to the GPL license that allows for commercial use.